1. Field of the Invention
This invention relates to the process for increasing the oxidative and/or thermal stability of quinone-coupled polyphenylene oxides by contacting the quinone-coupled polyphenylene oxides with a capping agent in the presence of a water soluble base and a catalytic phase transfer agent.
2. Description of the Prior Art
Hay et al., U.S. Ser. No. 613,072, now U.S. Pat. No. 4,048,143, discloses the capping of polyphenylene oxides having an average hydroxyl group per molecule of 1.0 or less as described in various U.S. patent applications including Hay's U.S. Pat. Nos. 3,306,879, 3,914,266; application Ser. No. 540,473, filed Jan. 13, 1975, now U.S. Pat. No. 4,028,341; a continuation-in-part of Ser. No. 441,295, filed Feb. 11, 1974, now abandoned; and Olander's U.S. Pat. Nos. 3,956,442, 3,965,069, 3,972,851; and Ser. No. 582,910, filed June 2, 1975, now U.S. Pat. No. 4,054,553. All the Hay and Olander disclosures referenced above are incorporated herein in their entirety by reference.
In White's copending U.S. patent application Ser. No. 800,635, filed on May 26, 1977, new polyphenylene oxide quinone-coupled polymers having an average hydroxyl group per molecule value greater than 0, including 2.0 or less are described. These new polymers either alone or in combination with polyphenylene oxide reaction products of the prior art, i.e. polyphenylene oxides having an average hydroxyl group per molecule value greater than zero including 1.0 or less can be capped as described in greater detail hereafter to form other polymers having increased oxidative and thermal stability.